Originally Posted by
gfunkdave
Generally Li-ion batteries are happiest if you store them with 50-70% charge. Storing with full charge is stressful on the cells (I forget why) and if they discharge too much they can become nonfunctional.
Is this really a problem with modern Li-ion batteries? I've kept some power banks I have fully charged repeatedly, over months, and have not seen any deterioration in functionality. My understanding is that most battery makers now include controls in the battery to prevent harmful levels of charging anyway, so when it says it's 100% charged it's already not really full but at some optimal level determined by the manufacturer, and we don't need to second-guess that.